Recreate as `serverless-agents-md-python` (rename for naming alignment)

This sample should be republished as a new repo named `serverless-agents-md-python` to align with the `serverless-agents-*` naming convention used by the canonical Functions exemplar quickstarts (see `functions-quickstart-serverless-agents-azd`).

## Proposed plan
1. Create a new repo `Azure-Samples/serverless-agents-md-python` from this content.
2. Update README and any doc references.
3. Archive this repo with a banner pointing to the new location.

## Why
- Consistent naming across the Functions exemplar matrix.
- Makes the Python/Markdown-agent sample discoverable alongside the other serverless-agents quickstarts.